Deterministic polarization states in partially coherent vector light beams
Phys. Rev. A 114, 023519 – Published 24 August, 2026
DOI: https://doi.org/10.1103/hp1z-npyg
Abstract
Partially coherent vector beams generally undergo depolarization during propagation due to the incoherent superposition of spatial modes with different polarization states. Here we show that deterministic polarization states can, nevertheless, emerge in a partially coherent beam at a prescribed propagation distance. This effect is achieved by encoding mutually uncorrelated off-axis vector modes into a partially coherent and partially polarized source using a fractional Fourier transform optical system. During subsequent free-space propagation, the displaced vector modes evolve into overlapping and synchronized vector beams in a designed plane. As a result, the beam becomes fully polarized while remaining spatially partially coherent. The underlying mechanism is interpreted in terms of the cross-spectral density phase evolution of two orthogonally polarized partially coherent scalar modes that synthesize the partially coherent vector beam. Our results reveal a different route for controlling polarization structures in partially coherent light, with potential applications in optical angular momentum manipulation and optical trapping.
